Fireball at the Track
10-16-2003, 01:36 AM
#1
Burning Brakes
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Fireball at the Track
Attached is a picture of what used to be a flywheel oil seal.
Following last weeks exciting episode of the intercooler hose blowing off....
This weeks sequel track day ended in a fireball
It was my third hotlap, and then boom!... white smoke... fire et.al...
Fortunately, The oil fire subsided after allowing the car to coast. (was about 10 o'clock temp)
No oil pressure lost, no warning lights.
The oil breached the flywheel housing and ended up going back up the transmission vacumn and into the airbox. This resulted in oil blowing through the entire engine and intercooler. The result were not pretty.
I did a search on "fly wheel oil seal", "oil seals" etc and didn't find anything that was relevant.
I'm guessing that this isn't something that happens commonly... seeing as the flywheel oil seal is not a pressurised component.
I am in search of a probable cause, or at least the most likely root problem creating the catastrophic failure of a seemingly benign seal.
Any opinions, speculations, experience or insight will come much appreciated
10-16-2003, 03:44 AM
#2
RL Technical Advisor
Hi:
Well, for sure this not common,....
There is crankcase pressure behind that seal to some degree and the only thing I can speculate about is that perhaps the seal was either not installed correctly or defective.
Its also possible that excessive crankcase pressure pushed out against the rotating flywheel which tore it the rest of the way. There is a pretty fair amount of pressure in the case at high RPM.
My vote goes to incorrect installation, perhaps when a new clutch was fitted. I have no history about the engine, of course.
Well, for sure this not common,....
There is crankcase pressure behind that seal to some degree and the only thing I can speculate about is that perhaps the seal was either not installed correctly or defective.
Its also possible that excessive crankcase pressure pushed out against the rotating flywheel which tore it the rest of the way. There is a pretty fair amount of pressure in the case at high RPM.
My vote goes to incorrect installation, perhaps when a new clutch was fitted. I have no history about the engine, of course.
10-16-2003, 04:02 AM
#3
Burning Brakes
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Steve,
Thanks for the Insight.
Heres a little more info, I hope it helps:
I noticed some scoring on the flywheel, which perhaps is a good indicator that the seal had worked itself loose under pressure slowly.
The clutch was recently changed, together with an entire head rebuild... worn/overheated valve guides. (3k run in and 2k on the street)
The only other plausible explanation other than a poor installation is if the oiling system is somehow backing up due to a return flow problem... hence causing a pressure buildup. The swelling pressure may have dislodged the seal slowly untill the seal eventually got caught on the flywheel and tore itself clean off.
My mechanic thinks the above scenerio is extremely unlikely as he feels that the 993TT engine is very sensitive to oiling problems. Should the oiling system have a problem, he believes that the engine would seize immediately and we would see the problems manifest in other ways.
If this behavior is abnormal, then perhaps it should be a warranty job?... afterall, it makes sense that the original seal was replaced by the shop after the rebuild.
Many thanks in advance!
SYF
Thanks for the Insight.
Heres a little more info, I hope it helps:
I noticed some scoring on the flywheel, which perhaps is a good indicator that the seal had worked itself loose under pressure slowly.
The clutch was recently changed, together with an entire head rebuild... worn/overheated valve guides. (3k run in and 2k on the street)
The only other plausible explanation other than a poor installation is if the oiling system is somehow backing up due to a return flow problem... hence causing a pressure buildup. The swelling pressure may have dislodged the seal slowly untill the seal eventually got caught on the flywheel and tore itself clean off.
My mechanic thinks the above scenerio is extremely unlikely as he feels that the 993TT engine is very sensitive to oiling problems. Should the oiling system have a problem, he believes that the engine would seize immediately and we would see the problems manifest in other ways.
If this behavior is abnormal, then perhaps it should be a warranty job?... afterall, it makes sense that the original seal was replaced by the shop after the rebuild.
Many thanks in advance!
SYF
10-16-2003, 04:25 AM
#4
Hi SYF,
Hmmmm..... I agree with Steve. Looks like a bad install which puts it as a warranty claim. I asked around and no one that I know of has had this problem. Bu can you get the shop that did the rebuild to accept responsibility?
You might want to check crankcase pressures though. And the crankcase ventilation system. I'll try and see if I can dig up some info on this and get back to you as well.
Really sorry to read about this SYF . Hope you have her back quick...
cheers,
Hmmmm..... I agree with Steve. Looks like a bad install which puts it as a warranty claim. I asked around and no one that I know of has had this problem. Bu can you get the shop that did the rebuild to accept responsibility?
You might want to check crankcase pressures though. And the crankcase ventilation system. I'll try and see if I can dig up some info on this and get back to you as well.
Really sorry to read about this SYF
. Hope you have her back quick...cheers,
10-16-2003, 05:50 AM
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Burning Brakes
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Krish,
Fortunately, the dealer has agreed to take it under warranty. It is nice to have the job taken care by the dealer, seeing as they charged an arm and a leg for the initial work done.
Unfortunately, I have not heard a reasonable explanation (other than Steve's) as to the possible causes for this.
Above and beyond the car condition, is my own personal safety. Don't get me wrong, I love my car
i just don't want to end up trapped in it, should another oil fire breakout. 
also, I've seen cases where oil gets sprayed onto the tires at high speed... potentially a big off on the track. (esp turn 6 in PG... downhill high speed camber corner)
baffling isn't it!
oh well... we'll just have to see what happens next
Fortunately, the dealer has agreed to take it under warranty. It is nice to have the job taken care by the dealer, seeing as they charged an arm and a leg for the initial work done.
Unfortunately, I have not heard a reasonable explanation (other than Steve's) as to the possible causes for this.
Above and beyond the car condition, is my own personal safety. Don't get me wrong, I love my car
i just don't want to end up trapped in it, should another oil fire breakout. also, I've seen cases where oil gets sprayed onto the tires at high speed... potentially a big off on the track. (esp turn 6 in PG... downhill high speed camber corner)
baffling isn't it!
oh well... we'll just have to see what happens next
10-16-2003, 07:32 AM
#6
Burning Brakes
geez....Your "factory stock" sure gives u trouble huh...
Lucky you still have "factory warranty"
You do thru those guys at RUf SEA right?
All the best....hope u get ur car fixed so we can go driving at Sepang in Dec...
Lucky you still have "factory warranty"
You do thru those guys at RUf SEA right?
All the best....hope u get ur car fixed so we can go driving at Sepang in Dec...
10-16-2003, 08:11 AM
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Superyellowfly,
Now I understand your PM. I would also guess a couple of things described by Steve as I did have a similatrthing happen to me on the track (although not to this degree). I would bet that there is a problem when they removed the engine and reinstalled it somwhere in the ventilation lines of the oil system. Also, more that likely your oil seal was also not properly installed and then with the ventilation issue building too much crankcase pressure it was a REAL problem.
I had a 3.2 engine in my race car that I also had removed by a shop when they did some head work. Next time out at the track I has half way through a run group and there was oil smell and smoke coming from my car. When I go to the pits I found my engine COMPLETELY covered in oil inside the engine compartment. The culprit turned out to be a restrictor inside one of the oil lines was turned sideways when the engine was reinstalled and was pretty much blocking the line. The result was a massive amount of crankcase pressure under high RPMs (as Steve described) blowing out everywhere...
After this incident, I found other with similar problems when a shop had removed the engine and reinstall and leave a shop towel or some type of plug in the line and then when the line is resintalled, instant blockage. Most of the people I found said their cars drove fine, but then as with your situation they were driving aggressively, bad things started to happen.
Good luck and glad the damage was not worse.
Now I understand your PM. I would also guess a couple of things described by Steve as I did have a similatrthing happen to me on the track (although not to this degree). I would bet that there is a problem when they removed the engine and reinstalled it somwhere in the ventilation lines of the oil system. Also, more that likely your oil seal was also not properly installed and then with the ventilation issue building too much crankcase pressure it was a REAL problem.
I had a 3.2 engine in my race car that I also had removed by a shop when they did some head work. Next time out at the track I has half way through a run group and there was oil smell and smoke coming from my car. When I go to the pits I found my engine COMPLETELY covered in oil inside the engine compartment. The culprit turned out to be a restrictor inside one of the oil lines was turned sideways when the engine was reinstalled and was pretty much blocking the line. The result was a massive amount of crankcase pressure under high RPMs (as Steve described) blowing out everywhere...
After this incident, I found other with similar problems when a shop had removed the engine and reinstall and leave a shop towel or some type of plug in the line and then when the line is resintalled, instant blockage. Most of the people I found said their cars drove fine, but then as with your situation they were driving aggressively, bad things started to happen.
Good luck and glad the damage was not worse.
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10-16-2003, 03:57 PM
#8
Burning Brakes
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Thanks guys!
The advice and insight is most helpful.
I'll present all the possible migtigating factors and see what we can narrow it down to...
Steve, Bob,
With the insight provided, at least i have a reasonable starting point to make logical deductions as to the causative reasons.
I think theres definitely more than meets the eye.... Porsches were built for endurance racing... there remains much to be said when a porsche only lasts three hot laps.
Will report more details and outcomes when i get a chance.
Krish,
I believe theres a PCS event on the 25th this month... will you be there?
The advice and insight is most helpful.
I'll present all the possible migtigating factors and see what we can narrow it down to...
Steve, Bob,
With the insight provided, at least i have a reasonable starting point to make logical deductions as to the causative reasons.
I think theres definitely more than meets the eye.... Porsches were built for endurance racing... there remains much to be said when a porsche only lasts three hot laps.
Will report more details and outcomes when i get a chance.
Krish,
I believe theres a PCS event on the 25th this month... will you be there?
10-18-2003, 05:37 PM
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Looks like anything I could think of has already been covered. Best of luck getting the car back in order.
Please let us know what the diagnosis is once they have it completely apart.
Please let us know what the diagnosis is once they have it completely apart.
10-20-2003, 06:56 AM
#10
Burning Brakes
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To conclude this thread,
The dealer did take it under warranty...
I'm not sure if that makes it an admission of guilt or just a show of good faith.
In anycase, I have my car back and she seems to be running just fine.
I'll be hitting the track this weekend, hopefully the next post will read "pics of trackday" and not "fireball part two"
Many thanks to those who responded and provided valuable insight. It did help me narrow down the causes fairly substantially and make the investigative work more focused.
Thanks guys!
The dealer did take it under warranty...
I'm not sure if that makes it an admission of guilt or just a show of good faith.
In anycase, I have my car back and she seems to be running just fine.
I'll be hitting the track this weekend, hopefully the next post will read "pics of trackday" and not "fireball part two"
Many thanks to those who responded and provided valuable insight. It did help me narrow down the causes fairly substantially and make the investigative work more focused.
Thanks guys!
10-20-2003, 01:27 PM
#13
Burning Brakes
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Fongster,
Sepang International Circuit
Bob,
The good news is, my car is back.
The bad news is, the cams need adjustment... hence won't be doing too many highspeed runs anytime soon.
Which pics would you like?
Sepang International Circuit
Bob,
The good news is, my car is back.
The bad news is, the cams need adjustment... hence won't be doing too many highspeed runs anytime soon.
Which pics would you like?
10-20-2003, 09:45 PM
#14
Superyellowfly,
Glad to hear she's back on the road! Didn't get back to you earlier as I was preparing to run an event last weekend, the MSS. To your question, yes I'll be there, looking forwrd to meeting up if it happens ! On your blown seal. after looking through some info I had it would appear the most likely culprit was a blocked crancase vent line. Glad to hear though that the shop covered it, really decent bunch by the sound of it!
Glad to hear she's back on the road! Didn't get back to you earlier as I was preparing to run an event last weekend, the MSS. To your question, yes I'll be there, looking forwrd to meeting up if it happens
! On your blown seal. after looking through some info I had it would appear the most likely culprit was a blocked crancase vent line. Glad to hear though that the shop covered it, really decent bunch by the sound of it!
10-21-2003, 12:12 AM
#15
Burning Brakes
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Krish,
By the sounds of it, I'll be seeing you this weekend then!
I probably won't be driving the Ruf up, seeing as i don't have fresh tires. If you don't mind, I'll bum a ride instead
Perhaps time for some video footage... I'll bring my tripod and camera in case
I guess the dealers/stealers aren't so bad afterall
By the sounds of it, I'll be seeing you this weekend then!
I probably won't be driving the Ruf up, seeing as i don't have fresh tires. If you don't mind, I'll bum a ride instead
Perhaps time for some video footage... I'll bring my tripod and camera in case
I guess the dealers/stealers aren't so bad afterall